Assessing the Quality of Data from Continuously Operating Reference Stations in Ghana

Abstract

Assessing the Quality of Data from Continuously Operating Reference Stations In Ghana Since 2019, Ghana has witnessed the establishment of new Continuously Operating Reference Stations (CORS) sites by the Licensed Surveyors Association of Ghana (LISAG) to augment the five existing CORS which were established in 2007 by Government of Ghana. However, limited study has been carried out on quality of data from these CORS stations regarding the standards set out by the International GNSS service (IGS) Site Guidelines, 2015. This study presents preliminary reports on pseudorange multipath effects, cycle slips and data completeness in CORS data using Translate, Edit and Quality Check (TEQC) software. The study used data observed simultaneously from receivers mounted at different sites with interstation distances of up to 200km. The results showed noticeable variations in the quality parameters measured at the CORS stations. The Root Mean Square (RMS) values of pseudorange multipath on L1 signal (MP1) and L2 signal (MP2) at the test stations were within the threshold of 0.5m contained in IGS Site Guidelines of 2015. All observed CORS data were available between 99.07% and 100% completeness which is well above the 95% thresholds set by IGS. The CORS stations recorded cycle slip counts fluctuating between 4 and 16. The study concluded that multipath effects in Ghana are location dependent with higher variability. Quality reports on CORS data provide useful information to CORS operators and users for decision making.